( Reaffirmed 2004 ) IS : 9452(Part 11) - 1980 Indian Standard CODE OF PRACTICE FOR MEASUREMENT OF SEEPAGE LOSSES FROM CANALS PART II INFLOW-O~UTFLOW METHOD Canals and Canal Linings Sectional Committee, Chairman SHRI S. B. KHARE Chukha BDC 57 Representing Hyde1 Project, Bhutan Members ADDITIONALDIRECTOR ADMINISTRATOR SHRI N. C. BHATNAGAR SHRI CHICKARMANE SHRI S. K. KARAMCHANDANI Irrigation and Research Institute, Khagaul ( Patna ) Irrigation Department, Government of Maharashtra, Bombay Central Ground Water Board, Chandigarh Union Carbide India Ltd, Bombay Irrigation and Power Department, Andhra Pradesh, Hyderabad Government of ( AZternate ) CHIEF ENGINEER DR J. PURUSHOTHAM ( Alternate ) Irrigation Government of Works, Punjab, CHIEF ENGINEER( C 1 Chandigarh DIRECTORCENTRAL DESIGNS ( Alternate ) Public Works Department, Government of Tamil CHIEF ENGINEER ( IRRIGATION) Nadu, Madras SENIORDEPUTY CHIEF ENGINEER ( IRRIGATION) ( Alternate ) CHIEF ENGINEER ( IRRIGATION ) Public Works Department, Government of Karnataka, Bangalore ( SOUTH ) C H I E F ENGINEER ( TUNGABHADRAPROJECT) ( Alternate ) Beas Designs Organization, Nangal Township SHRI 0. P. DATTA Irrigation Department, Government of Rajasthan, DIRECTOR Jaipur Central Water Commission, New Delhi DIRECTOR ( B & CD-I ) DEPUTY DIRECTOR ( B & CD-I) ( Alternate ) ( Continued on page 2 ) @ Copyright INDIAN STANDARDS 1980 INSTITUTION This publication is protected under the Indian Copyright Act ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act. IS : 9452 ( Part II ) - 1980 ( Continued from page 1 ) Representing Central Water Commission, New Delhi Members DIRECTOR ( B & CD-II ) DEPUTY DIRECTOR( B & CD-II DR R. J. GARDE I Alternate j \ -~ ' ) Water Resources Development Training Centre, University of Roorkee, Roorkee (U.P.) DR A. S. CHAWLA ( Alternate SHRI K. M. MAHESHWARI ) SHRI N. K. DIKSHIT ( Alternate ) SHRI Y. K. MEHTA Concrete Association of India, Bombay SHRI E. T. ANTIA ( Alternate ) Irrigation Deoartment, Government of Uttar SHRI GAURI KANT MISRA -Pradesh, iucknow SHRI R. K. AGGARWAL ( Alternate ) Fibreglass Pilkington, Bombay SHRI G. H. RODRICKS SHRI E. SUBRAMANIAN ( Alternate ) SHRI P. C. SAXENA Central Water and Power Research Station, Pune SHRI V. P. BHA~ ( Alternate ) Central Board of Irrieation and Power. New Delhi SECRETARY Irrigation Research fnstitute, Roorkee SHRI M. K. SINGHAL SHRI JAGDISHMOHAN ( Alternate ) Irrigation and Power Department, Government of SHRI K. T. SUBUDHI Orissa, Bhubaneshwar SUPERINTENDING E N G I N E E R Irrigation and Power Department, Government of Haryana, Chandigarh ( PROJECT& DESIGNCIRCLE ) SUPERINTENDINGENGINEER ( S. Y. L. DESIGN CIRCLE ) SHRI D. AJITHA SIMHA, Director ( Civ Engg ) Plannina Commission. De&i Government of India. New ( Alfernate ) Director General, IS1 ( Ex-oficio Member ) Secretary SHRI V. KALYANASUNDARAM Assistant Director ( Civ Engg ), IS1 2 I§ : 9452 ( Part II ) - 1980 In-dian Standard CODE OF PRACTICE FOR MEASUREMENT OF SEEPAGE LOSSES FROM CANALS PART II INFLOW-OUTFLOW METHOD 0. FOREWORD 0.1This Indian Standard was adopted by the Indian Standards Institution on 30 January 1980, after the draft finalized by the Canals and Canal Linings Sectional Committee had been approved by the Civil Engineering Division Council. 0.2 Irrigation project design, operation and maintenance, and canal lining research and development require accurate and economical measurement of seepage rates. The possible benefits from canal lining are saving in water, elimination of water logging, and reduction in ~maintenance cost. Hence, correct assessment of seepage losses from unlined canals is very important for evaluation of benefits from lining and field observations are the best means to make realistic assessment. 0.3 The loss of water by seepage from unlined canals in India generally varies from 0.3 to 7.0 m3/s/106 m2 depending on the permeability of soil through which the canal passes, location of water table, distance of drainage, bed width, side slope and water depth inside the canal. In addition, flow velocity, soil and water temperature, atmospheric pressure and stratification of the underlying soil also affect the seepage rate. 0.4 The seepage losses from unlined canals can be calculated by analytical methods or determined by direct measurements on the canals. The analytical calculations of seepage losses based on coefficient of hydraulic conductivity of soil and the boundary conditions of the flow system, are of particular value for the canals which are in the planning stage. The method of direct measurement of seepage losses are applicable to the existing canals. 0.5 Currently, accepted methods for direct measurement of seepage losses from existing canals are the inflow-outflow, ponding and seepage meter. In addition, there are special methods such as tracer technique, electrical logging or resistivity measurement, piezometric surveys and remote sensing. The inflow-outflow and ponding methods are applicable regardless of canal 3 IS : 9452 ( Part II ) - 1980 or soil conditions. The seepage meter cannot be used where the channel has rocky bottom or heavy weed growth. The tracer technique is best suited to canals in homogeneous and istropic formations. 0.5.1 The code of practice for measurement of seepage losses -from canals is being published in two parts, Part I dealing with ponding method and Part II dealing with inflow-outflow method. 0.6 Valuable assistance has been rendered by Dr A. S. Chawla, Professor, Water Resources Development and Training Centre, Roorkee in the preparation of this standard. , 1. SCOPE 1.1 This standard ( Part II ) deals with measurement open canals by inflow-outflow method. METHOD of seepage losses in 2. INFLOW-OUTFLOW 2.1 The inflow-outflow method consists in measuring the water that flows into and out of the section of canal being studied. The difference~of water quantities flowing into and out of the canal reach is attributed to seepage. Evaporation from the canal water surface and precipitation is also taken into consideration. In' order to apply corrections due to evaporation, an evaporation pan shall be used for measuring the evaporation rates during the tests. To determine evaporation, a reference may be made to IS : 6939-1973*. The method can be applied to canals of any size. 3. SELECTION OF TEST SITE 3.1 The selection of the site shall be governed by the availability of the measuring service at the site of inflow and outflow and accuracy of the measuring devices. The standard measuring devices such as standing wave flumes, V-notches, rectangular notches, etc, shall be preferred for measurement of discharges. The measuring device should be independent of downstream waterlevel, that is, submergence effect. 3.2 The length of the reach shall be such that the losses from the reach, measured by this method, are of a higher order compared to the accuracy of the measuring devices at inflow and outflow. 3.3 Where permanent existing measuring devices are not available, canal falls may be used. The falls can be calibrated to obtain head-discharge relationship. *Methods for determination pf avaporation from reservoirs. 4 IS :-9452 ( Part II) - 1980 3.4 Where' facilities mentioned above are not available, the discharge shall be assessed by current meter gauging. The current meter gauging site shall be selected such that the canal has well defined section in a straight reach ( for details reference may be made to IS: 1192-1959* ). 4. PRELIMINARY PROCEDURE 4.1 ARRANGEMENT AND EXPERIMENTAL Having selected the site for tests following preliminary shall be made: arrangements a) As far as possible all outlets from the canal shall be kept closed. In case it is unavoidable, some of the outlets may be kept open. The outlets decided to be kept closed during the test period shall be kept closed and locked. Similarly the outlets which are required to be kept open shall be locked wherever possible in a condition to ensure constant opening during the period of test; and b) The measuring devices should be checked for their dimensions and efficiency in giving accurate discharges. 4.2 Known discharge canal. The discharge 4.3 All diversions and the discharges through from the parent canal or reservoir is let into the shall be kept constant during the period oftests. losses from and inflow into the test reach including the open outlets should be measured accurately. 4.4 Apart from measuring the discharge, the water level in the test -reach of the canal shall also be recorded. In order to obtain consistent and accurate results, the steady water level condition shall be ensured at different sites. 4.5 The water level at the sites for which stage-relation is known and has been tested shall be recorded at an interval of 3 to 6 hours ( see Appendix A ). The observation shall be continued after the steady state condition has reached. This is indicated by the steady gauges at various sites. 5. ANALYSIS OF THE RESULTS 5.1 The data collected at different gauging sites is considered and recorded on a proforma shown in Appendix B. The period when gauges become constant, is considered as the period of the steady state conditions in respect of seepage. These gauge levels corresponding to this period are made use of for computing the discharges at inflow site, at outflow site and at various intermediate sites. The discharges are computed from gaugedischarge curves. 5.2 After the discharges are computed they are entered in a schematic sketch showing the position of different measuring devices and the I discharges let out therefrom. The sketch is similar to one as follows: *Velocity-area methods for measurement of flow of water in open channels. 5 IS : 9452 ( Part II ) - 1980 /L-/ In the sketch Q, and respectively. Q3 and Q4 ( L, +La+L, ) both from into the canal at distances from the inflow end. Q2 are the discharges at inflow and are the withdrawals at distances of the inflow end. Q, and Q, are the of (L,+L, ) and ( L,+L,+LB+L4 L, outflow and inflows ) both 5.3 If S is the average loss in m3/s per unit discharge in the canal per kilometre, the losses in the various reaches would work out as follows: Loss in reach I Loss in reach II Loss in reach III Loss in reach IV Loss in reach V = 41 = Q, SL, = qz = (Q,-Q,--41) % = q3 = ( Ql-Q3+Qa-ql-q2 = q4 = ( Q,-Q3+Q,-Q4-ql--q2-q3 = qa = (Qi-Qa-tQ,-Q,+Q,--4i-q2 -93-94 1 SL, = ) SL, ) SL, Total 10~s = q1+q2+q3+.q4+q5 Ql-Qs+Q~-Q~+Q,-Q, From these equations the value of S which is an average loss rate can be calculated. 5.4 If it is required to compute the seepage rate in terms of m3/s per million square metre of the wetted surface, A,, A,, Al, A, and A, instead of the lengths L,, L,, etc. as above are taken into consideration, the S being the average rate of seepage in m3/s per million square metre of the wetted surface. A,, A,, etc being the areas of the wetted surfaces in different reaches in million square metres. Loss in reach I Loss in reach II Loss in reach III = = = q1 = A,S q2 = A,S q3 = A3S 6 IS : 9452 ( Part II ) - 1980 Loss in reach IV Loss in reach V qi+qs+qa+q4+qa = = = q4 = A,S qa = A,S Q, -Q,-Q,+Q,+Q,-Qz From the above equations the values of S which is the average loss in m3/s per million square metre of wetted surface can be calculated. 6. LIMITATIONS 6.1 The inflow and outflow method has following limitations. 6.1.1 The losses worked out are the losses in the total experimental reach for the water table, temperature and humidity conditions in the reach at the time of the experiment. 6.1.2 The results obtained may not be accurate if the quantum of seepage loss is of low order, due to limitations of the instruments used for measuring discharges. 6.1.3 In case seepage losses are determined for a long section of the canal, it is not possible to know the distribution of seepage losses in various reaches. 6.1.4 When applied to a large reach of the canal, the steady state condition may be established after a long time, and it requires the arrangements of measurement of leakage and outflow from the off-taking channels. 6.1.5 Most. of the outlets in the canal will have to be closed when the measurements are going on. 7. ADVANTAGES 7.0 The inflow-outflow method has the following advantages. 7.1 The method can be applied without bringing canal out of operation thereby not affecting irrigation/power generation. 7.2 The method gives seepage losses under normal operating conditions. 7 IS ~9452 ( Part II ) - 1980 APPENDIX ( Clause 4.5 ) A PROFORMA OF OBSERVATIONS OF SEEPAGE LOSS BY INFLOW-OUTFLOW METHOD Name of Canal Location Type of Gauge Observer SL No. DATE TIME V II III IV REMARKS I GAUGE AT GAUGE AT GAUGEAT GAUGE AT GAUGE AT .*. . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Experiments closed on . . . . . . . . . . . . . . . . . . 8 IS : 9452 ( Part II ) - 1980 APPENDIX ( Clause 5.1 ) B STATEMENT SHOWING THE LOSSES IN CANALS BY INFLOW-OUTFLOW METHOD Name of Canal ................................. Observer ........................................... Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . ...*.... SL No. LENGTH AVERAGE INFLOW WETTED ma/s REOAPCH PERIMETER (km) Cm) OUTFLOW mS/s Loss mJ/s RATE OFLOSS IN 7*m3/s mS/S per per mS/sof million inflow square metre REMARKS 9 INDIAN ON CANALS IS: 3860-1966 STANDARDS AND CANAL LINXNGS 3872-1966 3873-1978 4515-1967 4558-1968 4701-1968 4745-1968 4839 (Part 4839 (Part Precast cement concrete slabs for canal linings Code of practice for lining of canals with burnt clay tiles Code of practice for laying in-sifu cement concrete lining on canals ( first revision ) Code of practice for boulder lining for canals Code of practice for~under-drainage of lined canals Code of practice for earthwork on canals Code of practice for design of cross section of lined canals I)-1979 Code of practice for maintenance of canals: Part I Unlined canals ( first revision ) II)-1979 Code of oractice for maintenance of canals: Part II Lined canals (`first revision ) of canals: plantation Part III Canal and regulation 4839 (Part III)-1979 Code of practice for maintenance structures, drains, outlets, jungle clearance ( first revision ) 4969-1968 5256-1969 5331-1969 5690-1969 5968-1968 6004-1971 6522-1972 6936-1973 7112-1973 7113-1973 7114-1973 7495-1974 7871-1975 7873-1975 7880-1975 7986-1976 8835-1978 9097-1979 9451-1980 9452 (Part 9452 (Part Method of test for determining Aexural strength of precast cement concrete slabs for canal lining Code of practice for sealing joints in concrete lining on canals Guide for selection of type of lining for canals Guide for laying combination lining for existing unlined canals Guide for planning and layout of canal system for irrigation Criteria for hydraulic design of sediment ejector for irrigation and power channels Criteria for design of silt vanes for sediment control in offtaking canals Criteria for location, selection and hydraulic design of canal escapes Criteria for design of cross section for unlined canals in alluvial soil Code of practice for soil-cement lining for canals Criteria for hydraulic design of cross regulators for canals Criteria for hydraulic design of silt selective head regulator for sediment control in offtaking canals Criteria for hydraulic design of groyne walls (curved wing) for sediment distribution at offtake points in a canal Code of practice for lime concrete lining for canals Criteria for hydraulic design of skimming platform for sediment control in offtaking canal Code of practice for canal outlets Guidelines for planning and design of surface drains Guide for laying lining of canals with hot bitumen or bituminous felts Guidelines for lining of canals in expansive soils I)-1980 Code of practice for measurement of seepage losses from canals: Part I Ponding method II)-1980 Code of practice for measurement of seepage losses from canals: Part II Inflow-outflow method